Question

Complete the following sentence.
The stem of a hydrometer is made narrow because it _________________ its sensitivity.
(A) Increases
(B) Decreases
(C) Independent
(D) Can’t say

Answer 1

Hint:- The hydrometer is used to measure the density of the liquid. And the stem of the hydrometer is the major part to measure the density of the liquid. Therefore the size of the stem is a determining factor for density.

Complete Step by step solution:
The hydrometer uses the concept of buoyancy for measuring the density of the liquid. The bottom portion is wider and hollow which helps for the buoyancy. The ballast helps for stability. The narrow stem will have measurements. To measure the density the liquid is poured to a large container. The hydrometer is immersed in the container and it will float freely after some time. The stem of the hydrometer and the surface of the liquid came to contact at a point. From the calculations the relative density of the liquid can be calculated. The scales in the hydrometer will be related to the density of the liquid.
If the stem size increases the accuracy of the measurement will decrease. For more accuracy the size of the stem should be narrow. Thus the sensitivity of the hydrometer increases.
The narrow stem increases the sensitivity of the hydrometer.
The answer is option A.

Note: If the density of the hydrometer is high the hydrometer will sink less because the weight displaced will be a small quantity when a body is immersed in it. And if the density is low, the hydrometer will sink more.